Introduction

The Republic of the Marshall Islands (MHL) is an island country near the equator in the Pacific Ocean, sharing maritime boundaries with the Federated States of Micronesia (FSM). The population of MHL was about 53,066 in 2016.

Because of its small size, UNWPP only provides estimates and predictions for the total population, not gender-divided, and no other fields. For VIMC purposes however, we need the full suite of fields like any other country as part of the set of GAVI countries.

UNWPP does however provide full data for the FSM, and due to its proximity, and similar kind of environment and heritage to MHL, it seems a suitable candidate to scale, to produce surrogate demographic dataset.

Method

For all of the data fields in UNWPP that are expressed as rates (mortality rate, birth rate, etc), we assume we can use UNWPP’s data for FSM as applying to MHL equivalently.

This also applies for the under-5 and under-1 child mortalities. We then use IGME’s neonatal mortality data (which is available for MHL) to produce a hybrid that is consistent with the rest of the data, while being guided by the real data we have. (See documentation of the child mortality algorithms)

Where the data fields are absolute numbers of people though; (number of deaths, number of people of certain age, etc), we want to use simple scaling, where the scaling factor is the population of MHL, divded by the population of FSM, as it was in the latest estimate - 2015.

While using a single scaling factor across the time series seems crude, when we could scale in a year-by-year way, it is necessary to provide internal consistency with the other UNWPP data for FSM. If we used the dynamic MHL/FSM fraction across all years, then we would have a very accurate-looking total population, but the rates of change for FSM that vary through time would not be consistent with the total population. Therefore, scaling of the whole population with a single factor is the necessary approach for consistency.

Note that these methods are applied after the population data is extended to included more detail for over-80 year olds, so the Marshall Islands data is based on data for FSM which has already been extended.

Total Population

Comparisons for scaled absolute numbers

The following graphs show for each statistic type represented by absolute numbers, (as opposed to rates), where we have scaled from FSM’s data to approximate MHL’s. We only have data on the total population to compare to.

Fertility

Population by age

UNWPP provide population data in two forms. The first, form is “quinquennial” (QQ), meaning the number of people in a 5-year age-band, reported at 5-year intervals. This is the resolution at which UNWPP’s source data is represented. The second form is “interpolated”, where UNWPP provide population data in 1-year age-bands, at single yearly intervals.

Mortality

Comparisons for adopted FSM rates

The following graphs show the rates and values that are not relative to population size, which we have assumed to be the same as FSM, and compare to external data.

Fertility

Migration

Data Sources